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Kairos Power secures $643M for Hermes 2 reactor in Tennessee

Kairos Power secures $643M for Hermes 2 reactor in Tennessee

Built World

Private investors and the US Department of Energy back the first power-producing Gen IV reactor in the country.

3 days ago: $643 million funding announced

Overview

Updated 1 hour ago

Kairos Power secured $643 million in private and federal funding for its Hermes 2 reactor in Oak Ridge, Tennessee. Investors provided $368 million; the US Department of Energy added $275 million.

Hermes 2 is a 50-megawatt fluoride salt-cooled high-temperature reactor, the first US Gen IV design to win a construction permit. It is slated to start up in 2030 and supply the TVA grid for Google data centers.

Most of the money goes to Hermes 2 construction; some covers Kairos's manufacturing expansion in Albuquerque, New Mexico. The project tests whether advanced reactors can be built on time and budget for the AI-era power surge.

Why it matters

Hermes 2 is the first US Gen IV reactor under construction; if it starts on schedule, it proves advanced reactors can feed the data-center power boom.

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Key Indicators

$643M
Total funding secured
Combined private investment and US Department of Energy financing announced in October 2026.
$368M
Private investment
Backers include Google Ventures, DCVC, and Samsung C&T.
$275M
US Department of Energy financing
Support through the Advanced Reactor Demonstration Program.
50 MWe
Hermes 2 planned capacity
Grid-connected power the plant will supply to the Tennessee Valley Authority.

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People Involved

Mike Laufer
Mike Laufer
Co-founder and chief executive officer, Kairos Power
Announced the $643 million funding package in October 2026

Organizations Involved

Kairos Power
Kairos Power
Nuclear energy startup
Building the Hermes 2 demonstration reactor in Oak Ridge, Tennessee

Develops fluoride salt-cooled high-temperature reactors using TRISO fuel and flibe coolant.
SE
Samsung C&T Engineering & Construction Group
South Korean construction and engineering company
Strategic investor and engineering partner in Kairos Power

South Korean builder providing up to $100 million in investment and engineering services to Kairos Power.
U.S. Department of Energy
U.S. Department of Energy
Federal agency
Provided $275 million in financing for Hermes 2

Federal agency financing Hermes 2 under its Advanced Reactor Demonstration Program.
Tennessee Valley Authority
Tennessee Valley Authority
Federal utility
Buyer of Hermes 2's power output

Federal utility that will take Hermes 2 generation onto its grid.
Google
Google
Technology company
Offtaker of Hermes 2 power via TVA

Alphabet company that agreed to buy Hermes 2 power for its data centers.
U.S. Nuclear Regulatory Commission
U.S. Nuclear Regulatory Commission
Federal regulatory agency
Issued Hermes 2 construction permits

Federal agency that licensed the Hermes 2 reactor facility.

Timeline

2021 October 2026

7 events Latest: 3 days ago
Tap a bar to jump to that date

  1. $643 million funding announced

    Latest Funding

    Kairos announces $643 million in combined private and US Department of Energy funding for Hermes 2.

  2. Samsung C&T term sheet

    Funding

    Kairos and Samsung C&T sign a term sheet for up to $100 million in investment and engineering services.

  3. Groundbreaking on Hermes 2

    Construction

    Kairos breaks ground on the Hermes 2 demonstration plant in Oak Ridge, Tennessee.

  4. Hermes 1 construction begins

    Construction

    Hermes 1 low-power demonstration reactor starts nuclear construction at the same Oak Ridge site.

  5. Hermes 2 construction permits issued

    Regulatory

    NRC issues construction permits for the Hermes 2 test reactor facility in Oak Ridge.

  6. First non-water-cooled reactor permit

    Regulatory

    NRC grants Kairos the first US construction permit for a non-water-cooled reactor in over 50 years.

  7. Kairos acquires Oak Ridge site

    Acquisition

    Kairos buys the K-33 and adjacent K-31 parcels in Oak Ridge for its reactor demonstration campus.

Scenarios

1

Hermes 2 connects to the grid by 2030

Possible Resolves by End of 2030

Discussed by: Kairos Power, Tennessee Valley Authority, and Bloomberg reporting

Kairos completes both Hermes 2 units on schedule, achieves first criticality, and delivers 50 megawatts to the TVA grid in 2030. Success would validate the KP-FHR design under real grid conditions and clear the path to full-scale commercial plants under the Google agreement.

2

First-of-kind delays push startup past 2031

Likely Resolves by End of 2031

Discussed by: Nuclear industry analysts citing cost-overrun precedents like NuScale's canceled UAMPS project

Licensing, supply-chain, or construction issues delay startup beyond 2030, consistent with the track record of first-of-kind reactor projects. Delays would raise costs and test investor patience, though the $275 million in DOE financing cushions the financial blow.

3

Hermes 2 success unlocks a full-scale fleet

Uncertain Resolves by End of 2028

Discussed by: Kairos Power and the Google multi-plant development agreement

A smooth Hermes 2 build validates the factory-built modular reactor model and the K-33 construction approach, prompting Kairos to announce orders for full-size commercial plants and expand the Google/TVA offtake. This would mark the move from demonstration to commerce.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2020-2023

NuScale and the UAMPS project (2020-2023)

NuScale became the first company to earn US design certification for a small modular reactor in 2023. But its flagship Utah project, the Utah Associated Municipal Power Systems plant, was canceled in November 2023 after power costs rose and participating utilities dropped out.

Then

The cancellation left NuScale without a near-term customer and cast doubt on the small modular reactor market.

Now

The project became the cautionary tale for first-of-kind reactor economics, pushing developers toward factory-built, modular designs as an alternative.

Why this matters now

Hermes 2 is the test of whether Kairos's modular, factory-built approach can avoid the cost and schedule overruns that sank NuScale's first project.

1943-present

Oak Ridge K-33 site (1940s to present)

The K-33 site at Oak Ridge was part of the Manhattan Project's gaseous diffusion complex, which enriched uranium for the first atomic bombs. The facility was later decommissioned, and the US Department of Energy cleaned up the land and returned it to the community for economic development.

Then

The reclaimed industrial land sat for years awaiting new use.

Now

Kairos bought the K-33 and adjacent K-31 parcels in 2021 to build its reactor campus, bringing nuclear innovation back to the same ground.

Why this matters now

Hermes 2 uses TRISO fuel and flibe coolant, proven nuclear technologies that originated in Oak Ridge, making the site a full-circle location for Gen IV development.

Sources

(8)
+2
Construction Review Bloomberg Law Kairos Power US Nuclear Regulatory Commission The Guru Investing.com Kairos Power Kairos Power